1 /* $OpenBSD: sshconnect2.c,v 1.166 2008/07/17 08:48:00 djm Exp $ */ 2 /* 3 * Copyright (c) 2000 Markus Friedl. All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 14 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 15 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 16 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 17 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 18 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 19 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 20 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 21 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 22 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 23 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 24 */ 25 26 #include "includes.h" 27 28 #include <sys/types.h> 29 #include <sys/socket.h> 30 #include <sys/wait.h> 31 #include <sys/stat.h> 32 33 #include <errno.h> 34 #include <netdb.h> 35 #include <pwd.h> 36 #include <signal.h> 37 #include <stdarg.h> 38 #include <stdio.h> 39 #include <string.h> 40 #include <unistd.h> 41 #if defined(HAVE_STRNVIS) && defined(HAVE_VIS_H) 42 #include <vis.h> 43 #endif 44 45 #include "openbsd-compat/sys-queue.h" 46 47 #include "xmalloc.h" 48 #include "ssh.h" 49 #include "ssh2.h" 50 #include "buffer.h" 51 #include "packet.h" 52 #include "compat.h" 53 #include "cipher.h" 54 #include "key.h" 55 #include "kex.h" 56 #include "myproposal.h" 57 #include "sshconnect.h" 58 #include "authfile.h" 59 #include "dh.h" 60 #include "authfd.h" 61 #include "log.h" 62 #include "readconf.h" 63 #include "misc.h" 64 #include "match.h" 65 #include "dispatch.h" 66 #include "canohost.h" 67 #include "msg.h" 68 #include "pathnames.h" 69 #include "uidswap.h" 70 71 #ifdef GSSAPI 72 #include "ssh-gss.h" 73 #endif 74 75 /* import */ 76 extern char *client_version_string; 77 extern char *server_version_string; 78 extern Options options; 79 80 /* 81 * SSH2 key exchange 82 */ 83 84 u_char *session_id2 = NULL; 85 u_int session_id2_len = 0; 86 87 char *xxx_host; 88 struct sockaddr *xxx_hostaddr; 89 90 Kex *xxx_kex = NULL; 91 92 static int 93 verify_host_key_callback(Key *hostkey) 94 { 95 if (verify_host_key(xxx_host, xxx_hostaddr, hostkey) == -1) 96 fatal("Host key verification failed."); 97 return 0; 98 } 99 100 void 101 ssh_kex2(char *host, struct sockaddr *hostaddr) 102 { 103 Kex *kex; 104 105 xxx_host = host; 106 xxx_hostaddr = hostaddr; 107 108 if (options.ciphers == (char *)-1) { 109 logit("No valid ciphers for protocol version 2 given, using defaults."); 110 options.ciphers = NULL; 111 } 112 if (options.ciphers != NULL) { 113 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 114 myproposal[PROPOSAL_ENC_ALGS_STOC] = options.ciphers; 115 } 116 myproposal[PROPOSAL_ENC_ALGS_CTOS] = 117 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_CTOS]); 118 myproposal[PROPOSAL_ENC_ALGS_STOC] = 119 compat_cipher_proposal(myproposal[PROPOSAL_ENC_ALGS_STOC]); 120 if (options.compression) { 121 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 122 myproposal[PROPOSAL_COMP_ALGS_STOC] = "zlib@openssh.com,zlib,none"; 123 } else { 124 myproposal[PROPOSAL_COMP_ALGS_CTOS] = 125 myproposal[PROPOSAL_COMP_ALGS_STOC] = "none,zlib@openssh.com,zlib"; 126 } 127 if (options.macs != NULL) { 128 myproposal[PROPOSAL_MAC_ALGS_CTOS] = 129 myproposal[PROPOSAL_MAC_ALGS_STOC] = options.macs; 130 } 131 if (options.hostkeyalgorithms != NULL) 132 myproposal[PROPOSAL_SERVER_HOST_KEY_ALGS] = 133 options.hostkeyalgorithms; 134 135 if (options.rekey_limit) 136 packet_set_rekey_limit((u_int32_t)options.rekey_limit); 137 138 /* start key exchange */ 139 kex = kex_setup(myproposal); 140 kex->kex[KEX_DH_GRP1_SHA1] = kexdh_client; 141 kex->kex[KEX_DH_GRP14_SHA1] = kexdh_client; 142 kex->kex[KEX_DH_GEX_SHA1] = kexgex_client; 143 kex->kex[KEX_DH_GEX_SHA256] = kexgex_client; 144 kex->client_version_string=client_version_string; 145 kex->server_version_string=server_version_string; 146 kex->verify_host_key=&verify_host_key_callback; 147 148 xxx_kex = kex; 149 150 dispatch_run(DISPATCH_BLOCK, &kex->done, kex); 151 152 session_id2 = kex->session_id; 153 session_id2_len = kex->session_id_len; 154 155 #ifdef DEBUG_KEXDH 156 /* send 1st encrypted/maced/compressed message */ 157 packet_start(SSH2_MSG_IGNORE); 158 packet_put_cstring("markus"); 159 packet_send(); 160 packet_write_wait(); 161 #endif 162 } 163 164 /* 165 * Authenticate user 166 */ 167 168 typedef struct Authctxt Authctxt; 169 typedef struct Authmethod Authmethod; 170 typedef struct identity Identity; 171 typedef struct idlist Idlist; 172 173 struct identity { 174 TAILQ_ENTRY(identity) next; 175 AuthenticationConnection *ac; /* set if agent supports key */ 176 Key *key; /* public/private key */ 177 char *filename; /* comment for agent-only keys */ 178 int tried; 179 int isprivate; /* key points to the private key */ 180 }; 181 TAILQ_HEAD(idlist, identity); 182 183 struct Authctxt { 184 const char *server_user; 185 const char *local_user; 186 const char *host; 187 const char *service; 188 Authmethod *method; 189 int success; 190 char *authlist; 191 /* pubkey */ 192 Idlist keys; 193 AuthenticationConnection *agent; 194 /* hostbased */ 195 Sensitive *sensitive; 196 /* kbd-interactive */ 197 int info_req_seen; 198 /* generic */ 199 void *methoddata; 200 }; 201 struct Authmethod { 202 char *name; /* string to compare against server's list */ 203 int (*userauth)(Authctxt *authctxt); 204 int *enabled; /* flag in option struct that enables method */ 205 int *batch_flag; /* flag in option struct that disables method */ 206 }; 207 208 void input_userauth_success(int, u_int32_t, void *); 209 void input_userauth_failure(int, u_int32_t, void *); 210 void input_userauth_banner(int, u_int32_t, void *); 211 void input_userauth_error(int, u_int32_t, void *); 212 void input_userauth_info_req(int, u_int32_t, void *); 213 void input_userauth_pk_ok(int, u_int32_t, void *); 214 void input_userauth_passwd_changereq(int, u_int32_t, void *); 215 216 int userauth_none(Authctxt *); 217 int userauth_pubkey(Authctxt *); 218 int userauth_passwd(Authctxt *); 219 int userauth_kbdint(Authctxt *); 220 int userauth_hostbased(Authctxt *); 221 int userauth_kerberos(Authctxt *); 222 223 #ifdef GSSAPI 224 int userauth_gssapi(Authctxt *authctxt); 225 void input_gssapi_response(int type, u_int32_t, void *); 226 void input_gssapi_token(int type, u_int32_t, void *); 227 void input_gssapi_hash(int type, u_int32_t, void *); 228 void input_gssapi_error(int, u_int32_t, void *); 229 void input_gssapi_errtok(int, u_int32_t, void *); 230 #endif 231 232 void userauth(Authctxt *, char *); 233 234 static int sign_and_send_pubkey(Authctxt *, Identity *); 235 static void pubkey_prepare(Authctxt *); 236 static void pubkey_cleanup(Authctxt *); 237 static Key *load_identity_file(char *); 238 239 static Authmethod *authmethod_get(char *authlist); 240 static Authmethod *authmethod_lookup(const char *name); 241 static char *authmethods_get(void); 242 243 Authmethod authmethods[] = { 244 #ifdef GSSAPI 245 {"gssapi-with-mic", 246 userauth_gssapi, 247 &options.gss_authentication, 248 NULL}, 249 #endif 250 {"hostbased", 251 userauth_hostbased, 252 &options.hostbased_authentication, 253 NULL}, 254 {"publickey", 255 userauth_pubkey, 256 &options.pubkey_authentication, 257 NULL}, 258 {"keyboard-interactive", 259 userauth_kbdint, 260 &options.kbd_interactive_authentication, 261 &options.batch_mode}, 262 {"password", 263 userauth_passwd, 264 &options.password_authentication, 265 &options.batch_mode}, 266 {"none", 267 userauth_none, 268 NULL, 269 NULL}, 270 {NULL, NULL, NULL, NULL} 271 }; 272 273 void 274 ssh_userauth2(const char *local_user, const char *server_user, char *host, 275 Sensitive *sensitive) 276 { 277 Authctxt authctxt; 278 int type; 279 280 if (options.challenge_response_authentication) 281 options.kbd_interactive_authentication = 1; 282 283 packet_start(SSH2_MSG_SERVICE_REQUEST); 284 packet_put_cstring("ssh-userauth"); 285 packet_send(); 286 debug("SSH2_MSG_SERVICE_REQUEST sent"); 287 packet_write_wait(); 288 type = packet_read(); 289 if (type != SSH2_MSG_SERVICE_ACCEPT) 290 fatal("Server denied authentication request: %d", type); 291 if (packet_remaining() > 0) { 292 char *reply = packet_get_string(NULL); 293 debug2("service_accept: %s", reply); 294 xfree(reply); 295 } else { 296 debug2("buggy server: service_accept w/o service"); 297 } 298 packet_check_eom(); 299 debug("SSH2_MSG_SERVICE_ACCEPT received"); 300 301 if (options.preferred_authentications == NULL) 302 options.preferred_authentications = authmethods_get(); 303 304 /* setup authentication context */ 305 memset(&authctxt, 0, sizeof(authctxt)); 306 pubkey_prepare(&authctxt); 307 authctxt.server_user = server_user; 308 authctxt.local_user = local_user; 309 authctxt.host = host; 310 authctxt.service = "ssh-connection"; /* service name */ 311 authctxt.success = 0; 312 authctxt.method = authmethod_lookup("none"); 313 authctxt.authlist = NULL; 314 authctxt.methoddata = NULL; 315 authctxt.sensitive = sensitive; 316 authctxt.info_req_seen = 0; 317 if (authctxt.method == NULL) 318 fatal("ssh_userauth2: internal error: cannot send userauth none request"); 319 320 /* initial userauth request */ 321 userauth_none(&authctxt); 322 323 dispatch_init(&input_userauth_error); 324 dispatch_set(SSH2_MSG_USERAUTH_SUCCESS, &input_userauth_success); 325 dispatch_set(SSH2_MSG_USERAUTH_FAILURE, &input_userauth_failure); 326 dispatch_set(SSH2_MSG_USERAUTH_BANNER, &input_userauth_banner); 327 dispatch_run(DISPATCH_BLOCK, &authctxt.success, &authctxt); /* loop until success */ 328 329 pubkey_cleanup(&authctxt); 330 dispatch_range(SSH2_MSG_USERAUTH_MIN, SSH2_MSG_USERAUTH_MAX, NULL); 331 332 debug("Authentication succeeded (%s).", authctxt.method->name); 333 } 334 335 void 336 userauth(Authctxt *authctxt, char *authlist) 337 { 338 if (authctxt->methoddata) { 339 xfree(authctxt->methoddata); 340 authctxt->methoddata = NULL; 341 } 342 if (authlist == NULL) { 343 authlist = authctxt->authlist; 344 } else { 345 if (authctxt->authlist) 346 xfree(authctxt->authlist); 347 authctxt->authlist = authlist; 348 } 349 for (;;) { 350 Authmethod *method = authmethod_get(authlist); 351 if (method == NULL) 352 fatal("Permission denied (%s).", authlist); 353 authctxt->method = method; 354 355 /* reset the per method handler */ 356 dispatch_range(SSH2_MSG_USERAUTH_PER_METHOD_MIN, 357 SSH2_MSG_USERAUTH_PER_METHOD_MAX, NULL); 358 359 /* and try new method */ 360 if (method->userauth(authctxt) != 0) { 361 debug2("we sent a %s packet, wait for reply", method->name); 362 break; 363 } else { 364 debug2("we did not send a packet, disable method"); 365 method->enabled = NULL; 366 } 367 } 368 } 369 370 void 371 input_userauth_error(int type, u_int32_t seq, void *ctxt) 372 { 373 fatal("input_userauth_error: bad message during authentication: " 374 "type %d", type); 375 } 376 377 void 378 input_userauth_banner(int type, u_int32_t seq, void *ctxt) 379 { 380 char *msg, *raw, *lang; 381 u_int len; 382 383 debug3("input_userauth_banner"); 384 raw = packet_get_string(&len); 385 lang = packet_get_string(NULL); 386 if (options.log_level >= SYSLOG_LEVEL_INFO) { 387 if (len > 65536) 388 len = 65536; 389 msg = xmalloc(len * 4); /* max expansion from strnvis() */ 390 strnvis(msg, raw, len * 4, VIS_SAFE|VIS_OCTAL); 391 fprintf(stderr, "%s", msg); 392 xfree(msg); 393 } 394 xfree(raw); 395 xfree(lang); 396 } 397 398 void 399 input_userauth_success(int type, u_int32_t seq, void *ctxt) 400 { 401 Authctxt *authctxt = ctxt; 402 if (authctxt == NULL) 403 fatal("input_userauth_success: no authentication context"); 404 if (authctxt->authlist) { 405 xfree(authctxt->authlist); 406 authctxt->authlist = NULL; 407 } 408 if (authctxt->methoddata) { 409 xfree(authctxt->methoddata); 410 authctxt->methoddata = NULL; 411 } 412 authctxt->success = 1; /* break out */ 413 } 414 415 void 416 input_userauth_failure(int type, u_int32_t seq, void *ctxt) 417 { 418 Authctxt *authctxt = ctxt; 419 char *authlist = NULL; 420 int partial; 421 422 if (authctxt == NULL) 423 fatal("input_userauth_failure: no authentication context"); 424 425 authlist = packet_get_string(NULL); 426 partial = packet_get_char(); 427 packet_check_eom(); 428 429 if (partial != 0) 430 logit("Authenticated with partial success."); 431 debug("Authentications that can continue: %s", authlist); 432 433 userauth(authctxt, authlist); 434 } 435 void 436 input_userauth_pk_ok(int type, u_int32_t seq, void *ctxt) 437 { 438 Authctxt *authctxt = ctxt; 439 Key *key = NULL; 440 Identity *id = NULL; 441 Buffer b; 442 int pktype, sent = 0; 443 u_int alen, blen; 444 char *pkalg, *fp; 445 u_char *pkblob; 446 447 if (authctxt == NULL) 448 fatal("input_userauth_pk_ok: no authentication context"); 449 if (datafellows & SSH_BUG_PKOK) { 450 /* this is similar to SSH_BUG_PKAUTH */ 451 debug2("input_userauth_pk_ok: SSH_BUG_PKOK"); 452 pkblob = packet_get_string(&blen); 453 buffer_init(&b); 454 buffer_append(&b, pkblob, blen); 455 pkalg = buffer_get_string(&b, &alen); 456 buffer_free(&b); 457 } else { 458 pkalg = packet_get_string(&alen); 459 pkblob = packet_get_string(&blen); 460 } 461 packet_check_eom(); 462 463 debug("Server accepts key: pkalg %s blen %u", pkalg, blen); 464 465 if ((pktype = key_type_from_name(pkalg)) == KEY_UNSPEC) { 466 debug("unknown pkalg %s", pkalg); 467 goto done; 468 } 469 if ((key = key_from_blob(pkblob, blen)) == NULL) { 470 debug("no key from blob. pkalg %s", pkalg); 471 goto done; 472 } 473 if (key->type != pktype) { 474 error("input_userauth_pk_ok: type mismatch " 475 "for decoded key (received %d, expected %d)", 476 key->type, pktype); 477 goto done; 478 } 479 fp = key_fingerprint(key, SSH_FP_MD5, SSH_FP_HEX); 480 debug2("input_userauth_pk_ok: fp %s", fp); 481 xfree(fp); 482 483 /* 484 * search keys in the reverse order, because last candidate has been 485 * moved to the end of the queue. this also avoids confusion by 486 * duplicate keys 487 */ 488 TAILQ_FOREACH_REVERSE(id, &authctxt->keys, idlist, next) { 489 if (key_equal(key, id->key)) { 490 sent = sign_and_send_pubkey(authctxt, id); 491 break; 492 } 493 } 494 done: 495 if (key != NULL) 496 key_free(key); 497 xfree(pkalg); 498 xfree(pkblob); 499 500 /* try another method if we did not send a packet */ 501 if (sent == 0) 502 userauth(authctxt, NULL); 503 } 504 505 #ifdef GSSAPI 506 int 507 userauth_gssapi(Authctxt *authctxt) 508 { 509 Gssctxt *gssctxt = NULL; 510 static gss_OID_set gss_supported = NULL; 511 static u_int mech = 0; 512 OM_uint32 min; 513 int ok = 0; 514 515 /* Try one GSSAPI method at a time, rather than sending them all at 516 * once. */ 517 518 if (gss_supported == NULL) 519 gss_indicate_mechs(&min, &gss_supported); 520 521 /* Check to see if the mechanism is usable before we offer it */ 522 while (mech < gss_supported->count && !ok) { 523 /* My DER encoding requires length<128 */ 524 if (gss_supported->elements[mech].length < 128 && 525 ssh_gssapi_check_mechanism(&gssctxt, 526 &gss_supported->elements[mech], authctxt->host)) { 527 ok = 1; /* Mechanism works */ 528 } else { 529 mech++; 530 } 531 } 532 533 if (!ok) 534 return 0; 535 536 authctxt->methoddata=(void *)gssctxt; 537 538 packet_start(SSH2_MSG_USERAUTH_REQUEST); 539 packet_put_cstring(authctxt->server_user); 540 packet_put_cstring(authctxt->service); 541 packet_put_cstring(authctxt->method->name); 542 543 packet_put_int(1); 544 545 packet_put_int((gss_supported->elements[mech].length) + 2); 546 packet_put_char(SSH_GSS_OIDTYPE); 547 packet_put_char(gss_supported->elements[mech].length); 548 packet_put_raw(gss_supported->elements[mech].elements, 549 gss_supported->elements[mech].length); 550 551 packet_send(); 552 553 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_RESPONSE, &input_gssapi_response); 554 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_TOKEN, &input_gssapi_token); 555 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERROR, &input_gssapi_error); 556 dispatch_set(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK, &input_gssapi_errtok); 557 558 mech++; /* Move along to next candidate */ 559 560 return 1; 561 } 562 563 static OM_uint32 564 process_gssapi_token(void *ctxt, gss_buffer_t recv_tok) 565 { 566 Authctxt *authctxt = ctxt; 567 Gssctxt *gssctxt = authctxt->methoddata; 568 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 569 gss_buffer_desc mic = GSS_C_EMPTY_BUFFER; 570 gss_buffer_desc gssbuf; 571 OM_uint32 status, ms, flags; 572 Buffer b; 573 574 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 575 recv_tok, &send_tok, &flags); 576 577 if (send_tok.length > 0) { 578 if (GSS_ERROR(status)) 579 packet_start(SSH2_MSG_USERAUTH_GSSAPI_ERRTOK); 580 else 581 packet_start(SSH2_MSG_USERAUTH_GSSAPI_TOKEN); 582 583 packet_put_string(send_tok.value, send_tok.length); 584 packet_send(); 585 gss_release_buffer(&ms, &send_tok); 586 } 587 588 if (status == GSS_S_COMPLETE) { 589 /* send either complete or MIC, depending on mechanism */ 590 if (!(flags & GSS_C_INTEG_FLAG)) { 591 packet_start(SSH2_MSG_USERAUTH_GSSAPI_EXCHANGE_COMPLETE); 592 packet_send(); 593 } else { 594 ssh_gssapi_buildmic(&b, authctxt->server_user, 595 authctxt->service, "gssapi-with-mic"); 596 597 gssbuf.value = buffer_ptr(&b); 598 gssbuf.length = buffer_len(&b); 599 600 status = ssh_gssapi_sign(gssctxt, &gssbuf, &mic); 601 602 if (!GSS_ERROR(status)) { 603 packet_start(SSH2_MSG_USERAUTH_GSSAPI_MIC); 604 packet_put_string(mic.value, mic.length); 605 606 packet_send(); 607 } 608 609 buffer_free(&b); 610 gss_release_buffer(&ms, &mic); 611 } 612 } 613 614 return status; 615 } 616 617 void 618 input_gssapi_response(int type, u_int32_t plen, void *ctxt) 619 { 620 Authctxt *authctxt = ctxt; 621 Gssctxt *gssctxt; 622 int oidlen; 623 char *oidv; 624 625 if (authctxt == NULL) 626 fatal("input_gssapi_response: no authentication context"); 627 gssctxt = authctxt->methoddata; 628 629 /* Setup our OID */ 630 oidv = packet_get_string(&oidlen); 631 632 if (oidlen <= 2 || 633 oidv[0] != SSH_GSS_OIDTYPE || 634 oidv[1] != oidlen - 2) { 635 xfree(oidv); 636 debug("Badly encoded mechanism OID received"); 637 userauth(authctxt, NULL); 638 return; 639 } 640 641 if (!ssh_gssapi_check_oid(gssctxt, oidv + 2, oidlen - 2)) 642 fatal("Server returned different OID than expected"); 643 644 packet_check_eom(); 645 646 xfree(oidv); 647 648 if (GSS_ERROR(process_gssapi_token(ctxt, GSS_C_NO_BUFFER))) { 649 /* Start again with next method on list */ 650 debug("Trying to start again"); 651 userauth(authctxt, NULL); 652 return; 653 } 654 } 655 656 void 657 input_gssapi_token(int type, u_int32_t plen, void *ctxt) 658 { 659 Authctxt *authctxt = ctxt; 660 gss_buffer_desc recv_tok; 661 OM_uint32 status; 662 u_int slen; 663 664 if (authctxt == NULL) 665 fatal("input_gssapi_response: no authentication context"); 666 667 recv_tok.value = packet_get_string(&slen); 668 recv_tok.length = slen; /* safe typecast */ 669 670 packet_check_eom(); 671 672 status = process_gssapi_token(ctxt, &recv_tok); 673 674 xfree(recv_tok.value); 675 676 if (GSS_ERROR(status)) { 677 /* Start again with the next method in the list */ 678 userauth(authctxt, NULL); 679 return; 680 } 681 } 682 683 void 684 input_gssapi_errtok(int type, u_int32_t plen, void *ctxt) 685 { 686 Authctxt *authctxt = ctxt; 687 Gssctxt *gssctxt; 688 gss_buffer_desc send_tok = GSS_C_EMPTY_BUFFER; 689 gss_buffer_desc recv_tok; 690 OM_uint32 status, ms; 691 u_int len; 692 693 if (authctxt == NULL) 694 fatal("input_gssapi_response: no authentication context"); 695 gssctxt = authctxt->methoddata; 696 697 recv_tok.value = packet_get_string(&len); 698 recv_tok.length = len; 699 700 packet_check_eom(); 701 702 /* Stick it into GSSAPI and see what it says */ 703 status = ssh_gssapi_init_ctx(gssctxt, options.gss_deleg_creds, 704 &recv_tok, &send_tok, NULL); 705 706 xfree(recv_tok.value); 707 gss_release_buffer(&ms, &send_tok); 708 709 /* Server will be returning a failed packet after this one */ 710 } 711 712 void 713 input_gssapi_error(int type, u_int32_t plen, void *ctxt) 714 { 715 OM_uint32 maj, min; 716 char *msg; 717 char *lang; 718 719 maj=packet_get_int(); 720 min=packet_get_int(); 721 msg=packet_get_string(NULL); 722 lang=packet_get_string(NULL); 723 724 packet_check_eom(); 725 726 debug("Server GSSAPI Error:\n%s", msg); 727 xfree(msg); 728 xfree(lang); 729 } 730 #endif /* GSSAPI */ 731 732 int 733 userauth_none(Authctxt *authctxt) 734 { 735 /* initial userauth request */ 736 packet_start(SSH2_MSG_USERAUTH_REQUEST); 737 packet_put_cstring(authctxt->server_user); 738 packet_put_cstring(authctxt->service); 739 packet_put_cstring(authctxt->method->name); 740 packet_send(); 741 return 1; 742 } 743 744 int 745 userauth_passwd(Authctxt *authctxt) 746 { 747 static int attempt = 0; 748 char prompt[150]; 749 char *password; 750 751 if (attempt++ >= options.number_of_password_prompts) 752 return 0; 753 754 if (attempt != 1) 755 error("Permission denied, please try again."); 756 757 snprintf(prompt, sizeof(prompt), "%.30s@%.128s's password: ", 758 authctxt->server_user, authctxt->host); 759 password = read_passphrase(prompt, 0); 760 packet_start(SSH2_MSG_USERAUTH_REQUEST); 761 packet_put_cstring(authctxt->server_user); 762 packet_put_cstring(authctxt->service); 763 packet_put_cstring(authctxt->method->name); 764 packet_put_char(0); 765 packet_put_cstring(password); 766 memset(password, 0, strlen(password)); 767 xfree(password); 768 packet_add_padding(64); 769 packet_send(); 770 771 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 772 &input_userauth_passwd_changereq); 773 774 return 1; 775 } 776 /* 777 * parse PASSWD_CHANGEREQ, prompt user and send SSH2_MSG_USERAUTH_REQUEST 778 */ 779 void 780 input_userauth_passwd_changereq(int type, u_int32_t seqnr, void *ctxt) 781 { 782 Authctxt *authctxt = ctxt; 783 char *info, *lang, *password = NULL, *retype = NULL; 784 char prompt[150]; 785 786 debug2("input_userauth_passwd_changereq"); 787 788 if (authctxt == NULL) 789 fatal("input_userauth_passwd_changereq: " 790 "no authentication context"); 791 792 info = packet_get_string(NULL); 793 lang = packet_get_string(NULL); 794 if (strlen(info) > 0) 795 logit("%s", info); 796 xfree(info); 797 xfree(lang); 798 packet_start(SSH2_MSG_USERAUTH_REQUEST); 799 packet_put_cstring(authctxt->server_user); 800 packet_put_cstring(authctxt->service); 801 packet_put_cstring(authctxt->method->name); 802 packet_put_char(1); /* additional info */ 803 snprintf(prompt, sizeof(prompt), 804 "Enter %.30s@%.128s's old password: ", 805 authctxt->server_user, authctxt->host); 806 password = read_passphrase(prompt, 0); 807 packet_put_cstring(password); 808 memset(password, 0, strlen(password)); 809 xfree(password); 810 password = NULL; 811 while (password == NULL) { 812 snprintf(prompt, sizeof(prompt), 813 "Enter %.30s@%.128s's new password: ", 814 authctxt->server_user, authctxt->host); 815 password = read_passphrase(prompt, RP_ALLOW_EOF); 816 if (password == NULL) { 817 /* bail out */ 818 return; 819 } 820 snprintf(prompt, sizeof(prompt), 821 "Retype %.30s@%.128s's new password: ", 822 authctxt->server_user, authctxt->host); 823 retype = read_passphrase(prompt, 0); 824 if (strcmp(password, retype) != 0) { 825 memset(password, 0, strlen(password)); 826 xfree(password); 827 logit("Mismatch; try again, EOF to quit."); 828 password = NULL; 829 } 830 memset(retype, 0, strlen(retype)); 831 xfree(retype); 832 } 833 packet_put_cstring(password); 834 memset(password, 0, strlen(password)); 835 xfree(password); 836 packet_add_padding(64); 837 packet_send(); 838 839 dispatch_set(SSH2_MSG_USERAUTH_PASSWD_CHANGEREQ, 840 &input_userauth_passwd_changereq); 841 } 842 843 static int 844 identity_sign(Identity *id, u_char **sigp, u_int *lenp, 845 u_char *data, u_int datalen) 846 { 847 Key *prv; 848 int ret; 849 850 /* the agent supports this key */ 851 if (id->ac) 852 return (ssh_agent_sign(id->ac, id->key, sigp, lenp, 853 data, datalen)); 854 /* 855 * we have already loaded the private key or 856 * the private key is stored in external hardware 857 */ 858 if (id->isprivate || (id->key->flags & KEY_FLAG_EXT)) 859 return (key_sign(id->key, sigp, lenp, data, datalen)); 860 /* load the private key from the file */ 861 if ((prv = load_identity_file(id->filename)) == NULL) 862 return (-1); 863 ret = key_sign(prv, sigp, lenp, data, datalen); 864 key_free(prv); 865 return (ret); 866 } 867 868 static int 869 sign_and_send_pubkey(Authctxt *authctxt, Identity *id) 870 { 871 Buffer b; 872 u_char *blob, *signature; 873 u_int bloblen, slen; 874 u_int skip = 0; 875 int ret = -1; 876 int have_sig = 1; 877 878 debug3("sign_and_send_pubkey"); 879 880 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 881 /* we cannot handle this key */ 882 debug3("sign_and_send_pubkey: cannot handle key"); 883 return 0; 884 } 885 /* data to be signed */ 886 buffer_init(&b); 887 if (datafellows & SSH_OLD_SESSIONID) { 888 buffer_append(&b, session_id2, session_id2_len); 889 skip = session_id2_len; 890 } else { 891 buffer_put_string(&b, session_id2, session_id2_len); 892 skip = buffer_len(&b); 893 } 894 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 895 buffer_put_cstring(&b, authctxt->server_user); 896 buffer_put_cstring(&b, 897 datafellows & SSH_BUG_PKSERVICE ? 898 "ssh-userauth" : 899 authctxt->service); 900 if (datafellows & SSH_BUG_PKAUTH) { 901 buffer_put_char(&b, have_sig); 902 } else { 903 buffer_put_cstring(&b, authctxt->method->name); 904 buffer_put_char(&b, have_sig); 905 buffer_put_cstring(&b, key_ssh_name(id->key)); 906 } 907 buffer_put_string(&b, blob, bloblen); 908 909 /* generate signature */ 910 ret = identity_sign(id, &signature, &slen, 911 buffer_ptr(&b), buffer_len(&b)); 912 if (ret == -1) { 913 xfree(blob); 914 buffer_free(&b); 915 return 0; 916 } 917 #ifdef DEBUG_PK 918 buffer_dump(&b); 919 #endif 920 if (datafellows & SSH_BUG_PKSERVICE) { 921 buffer_clear(&b); 922 buffer_append(&b, session_id2, session_id2_len); 923 skip = session_id2_len; 924 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 925 buffer_put_cstring(&b, authctxt->server_user); 926 buffer_put_cstring(&b, authctxt->service); 927 buffer_put_cstring(&b, authctxt->method->name); 928 buffer_put_char(&b, have_sig); 929 if (!(datafellows & SSH_BUG_PKAUTH)) 930 buffer_put_cstring(&b, key_ssh_name(id->key)); 931 buffer_put_string(&b, blob, bloblen); 932 } 933 xfree(blob); 934 935 /* append signature */ 936 buffer_put_string(&b, signature, slen); 937 xfree(signature); 938 939 /* skip session id and packet type */ 940 if (buffer_len(&b) < skip + 1) 941 fatal("userauth_pubkey: internal error"); 942 buffer_consume(&b, skip + 1); 943 944 /* put remaining data from buffer into packet */ 945 packet_start(SSH2_MSG_USERAUTH_REQUEST); 946 packet_put_raw(buffer_ptr(&b), buffer_len(&b)); 947 buffer_free(&b); 948 packet_send(); 949 950 return 1; 951 } 952 953 static int 954 send_pubkey_test(Authctxt *authctxt, Identity *id) 955 { 956 u_char *blob; 957 u_int bloblen, have_sig = 0; 958 959 debug3("send_pubkey_test"); 960 961 if (key_to_blob(id->key, &blob, &bloblen) == 0) { 962 /* we cannot handle this key */ 963 debug3("send_pubkey_test: cannot handle key"); 964 return 0; 965 } 966 /* register callback for USERAUTH_PK_OK message */ 967 dispatch_set(SSH2_MSG_USERAUTH_PK_OK, &input_userauth_pk_ok); 968 969 packet_start(SSH2_MSG_USERAUTH_REQUEST); 970 packet_put_cstring(authctxt->server_user); 971 packet_put_cstring(authctxt->service); 972 packet_put_cstring(authctxt->method->name); 973 packet_put_char(have_sig); 974 if (!(datafellows & SSH_BUG_PKAUTH)) 975 packet_put_cstring(key_ssh_name(id->key)); 976 packet_put_string(blob, bloblen); 977 xfree(blob); 978 packet_send(); 979 return 1; 980 } 981 982 static Key * 983 load_identity_file(char *filename) 984 { 985 Key *private; 986 char prompt[300], *passphrase; 987 int perm_ok, quit, i; 988 struct stat st; 989 990 if (stat(filename, &st) < 0) { 991 debug3("no such identity: %s", filename); 992 return NULL; 993 } 994 private = key_load_private_type(KEY_UNSPEC, filename, "", NULL, &perm_ok); 995 if (!perm_ok) 996 return NULL; 997 if (private == NULL) { 998 if (options.batch_mode) 999 return NULL; 1000 snprintf(prompt, sizeof prompt, 1001 "Enter passphrase for key '%.100s': ", filename); 1002 for (i = 0; i < options.number_of_password_prompts; i++) { 1003 passphrase = read_passphrase(prompt, 0); 1004 if (strcmp(passphrase, "") != 0) { 1005 private = key_load_private_type(KEY_UNSPEC, 1006 filename, passphrase, NULL, NULL); 1007 quit = 0; 1008 } else { 1009 debug2("no passphrase given, try next key"); 1010 quit = 1; 1011 } 1012 memset(passphrase, 0, strlen(passphrase)); 1013 xfree(passphrase); 1014 if (private != NULL || quit) 1015 break; 1016 debug2("bad passphrase given, try again..."); 1017 } 1018 } 1019 return private; 1020 } 1021 1022 /* 1023 * try keys in the following order: 1024 * 1. agent keys that are found in the config file 1025 * 2. other agent keys 1026 * 3. keys that are only listed in the config file 1027 */ 1028 static void 1029 pubkey_prepare(Authctxt *authctxt) 1030 { 1031 Identity *id; 1032 Idlist agent, files, *preferred; 1033 Key *key; 1034 AuthenticationConnection *ac; 1035 char *comment; 1036 int i, found; 1037 1038 TAILQ_INIT(&agent); /* keys from the agent */ 1039 TAILQ_INIT(&files); /* keys from the config file */ 1040 preferred = &authctxt->keys; 1041 TAILQ_INIT(preferred); /* preferred order of keys */ 1042 1043 /* list of keys stored in the filesystem */ 1044 for (i = 0; i < options.num_identity_files; i++) { 1045 key = options.identity_keys[i]; 1046 if (key && key->type == KEY_RSA1) 1047 continue; 1048 options.identity_keys[i] = NULL; 1049 id = xcalloc(1, sizeof(*id)); 1050 id->key = key; 1051 id->filename = xstrdup(options.identity_files[i]); 1052 TAILQ_INSERT_TAIL(&files, id, next); 1053 } 1054 /* list of keys supported by the agent */ 1055 if ((ac = ssh_get_authentication_connection())) { 1056 for (key = ssh_get_first_identity(ac, &comment, 2); 1057 key != NULL; 1058 key = ssh_get_next_identity(ac, &comment, 2)) { 1059 found = 0; 1060 TAILQ_FOREACH(id, &files, next) { 1061 /* agent keys from the config file are preferred */ 1062 if (key_equal(key, id->key)) { 1063 key_free(key); 1064 xfree(comment); 1065 TAILQ_REMOVE(&files, id, next); 1066 TAILQ_INSERT_TAIL(preferred, id, next); 1067 id->ac = ac; 1068 found = 1; 1069 break; 1070 } 1071 } 1072 if (!found && !options.identities_only) { 1073 id = xcalloc(1, sizeof(*id)); 1074 id->key = key; 1075 id->filename = comment; 1076 id->ac = ac; 1077 TAILQ_INSERT_TAIL(&agent, id, next); 1078 } 1079 } 1080 /* append remaining agent keys */ 1081 for (id = TAILQ_FIRST(&agent); id; id = TAILQ_FIRST(&agent)) { 1082 TAILQ_REMOVE(&agent, id, next); 1083 TAILQ_INSERT_TAIL(preferred, id, next); 1084 } 1085 authctxt->agent = ac; 1086 } 1087 /* append remaining keys from the config file */ 1088 for (id = TAILQ_FIRST(&files); id; id = TAILQ_FIRST(&files)) { 1089 TAILQ_REMOVE(&files, id, next); 1090 TAILQ_INSERT_TAIL(preferred, id, next); 1091 } 1092 TAILQ_FOREACH(id, preferred, next) { 1093 debug2("key: %s (%p)", id->filename, id->key); 1094 } 1095 } 1096 1097 static void 1098 pubkey_cleanup(Authctxt *authctxt) 1099 { 1100 Identity *id; 1101 1102 if (authctxt->agent != NULL) 1103 ssh_close_authentication_connection(authctxt->agent); 1104 for (id = TAILQ_FIRST(&authctxt->keys); id; 1105 id = TAILQ_FIRST(&authctxt->keys)) { 1106 TAILQ_REMOVE(&authctxt->keys, id, next); 1107 if (id->key) 1108 key_free(id->key); 1109 if (id->filename) 1110 xfree(id->filename); 1111 xfree(id); 1112 } 1113 } 1114 1115 int 1116 userauth_pubkey(Authctxt *authctxt) 1117 { 1118 Identity *id; 1119 int sent = 0; 1120 1121 while ((id = TAILQ_FIRST(&authctxt->keys))) { 1122 if (id->tried++) 1123 return (0); 1124 /* move key to the end of the queue */ 1125 TAILQ_REMOVE(&authctxt->keys, id, next); 1126 TAILQ_INSERT_TAIL(&authctxt->keys, id, next); 1127 /* 1128 * send a test message if we have the public key. for 1129 * encrypted keys we cannot do this and have to load the 1130 * private key instead 1131 */ 1132 if (id->key && id->key->type != KEY_RSA1) { 1133 debug("Offering public key: %s", id->filename); 1134 sent = send_pubkey_test(authctxt, id); 1135 } else if (id->key == NULL) { 1136 debug("Trying private key: %s", id->filename); 1137 id->key = load_identity_file(id->filename); 1138 if (id->key != NULL) { 1139 id->isprivate = 1; 1140 sent = sign_and_send_pubkey(authctxt, id); 1141 key_free(id->key); 1142 id->key = NULL; 1143 } 1144 } 1145 if (sent) 1146 return (sent); 1147 } 1148 return (0); 1149 } 1150 1151 /* 1152 * Send userauth request message specifying keyboard-interactive method. 1153 */ 1154 int 1155 userauth_kbdint(Authctxt *authctxt) 1156 { 1157 static int attempt = 0; 1158 1159 if (attempt++ >= options.number_of_password_prompts) 1160 return 0; 1161 /* disable if no SSH2_MSG_USERAUTH_INFO_REQUEST has been seen */ 1162 if (attempt > 1 && !authctxt->info_req_seen) { 1163 debug3("userauth_kbdint: disable: no info_req_seen"); 1164 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, NULL); 1165 return 0; 1166 } 1167 1168 debug2("userauth_kbdint"); 1169 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1170 packet_put_cstring(authctxt->server_user); 1171 packet_put_cstring(authctxt->service); 1172 packet_put_cstring(authctxt->method->name); 1173 packet_put_cstring(""); /* lang */ 1174 packet_put_cstring(options.kbd_interactive_devices ? 1175 options.kbd_interactive_devices : ""); 1176 packet_send(); 1177 1178 dispatch_set(SSH2_MSG_USERAUTH_INFO_REQUEST, &input_userauth_info_req); 1179 return 1; 1180 } 1181 1182 /* 1183 * parse INFO_REQUEST, prompt user and send INFO_RESPONSE 1184 */ 1185 void 1186 input_userauth_info_req(int type, u_int32_t seq, void *ctxt) 1187 { 1188 Authctxt *authctxt = ctxt; 1189 char *name, *inst, *lang, *prompt, *response; 1190 u_int num_prompts, i; 1191 int echo = 0; 1192 1193 debug2("input_userauth_info_req"); 1194 1195 if (authctxt == NULL) 1196 fatal("input_userauth_info_req: no authentication context"); 1197 1198 authctxt->info_req_seen = 1; 1199 1200 name = packet_get_string(NULL); 1201 inst = packet_get_string(NULL); 1202 lang = packet_get_string(NULL); 1203 if (strlen(name) > 0) 1204 logit("%s", name); 1205 if (strlen(inst) > 0) 1206 logit("%s", inst); 1207 xfree(name); 1208 xfree(inst); 1209 xfree(lang); 1210 1211 num_prompts = packet_get_int(); 1212 /* 1213 * Begin to build info response packet based on prompts requested. 1214 * We commit to providing the correct number of responses, so if 1215 * further on we run into a problem that prevents this, we have to 1216 * be sure and clean this up and send a correct error response. 1217 */ 1218 packet_start(SSH2_MSG_USERAUTH_INFO_RESPONSE); 1219 packet_put_int(num_prompts); 1220 1221 debug2("input_userauth_info_req: num_prompts %d", num_prompts); 1222 for (i = 0; i < num_prompts; i++) { 1223 prompt = packet_get_string(NULL); 1224 echo = packet_get_char(); 1225 1226 response = read_passphrase(prompt, echo ? RP_ECHO : 0); 1227 1228 packet_put_cstring(response); 1229 memset(response, 0, strlen(response)); 1230 xfree(response); 1231 xfree(prompt); 1232 } 1233 packet_check_eom(); /* done with parsing incoming message. */ 1234 1235 packet_add_padding(64); 1236 packet_send(); 1237 } 1238 1239 static int 1240 ssh_keysign(Key *key, u_char **sigp, u_int *lenp, 1241 u_char *data, u_int datalen) 1242 { 1243 Buffer b; 1244 struct stat st; 1245 pid_t pid; 1246 int to[2], from[2], status, version = 2; 1247 1248 debug2("ssh_keysign called"); 1249 1250 if (stat(_PATH_SSH_KEY_SIGN, &st) < 0) { 1251 error("ssh_keysign: no installed: %s", strerror(errno)); 1252 return -1; 1253 } 1254 if (fflush(stdout) != 0) 1255 error("ssh_keysign: fflush: %s", strerror(errno)); 1256 if (pipe(to) < 0) { 1257 error("ssh_keysign: pipe: %s", strerror(errno)); 1258 return -1; 1259 } 1260 if (pipe(from) < 0) { 1261 error("ssh_keysign: pipe: %s", strerror(errno)); 1262 return -1; 1263 } 1264 if ((pid = fork()) < 0) { 1265 error("ssh_keysign: fork: %s", strerror(errno)); 1266 return -1; 1267 } 1268 if (pid == 0) { 1269 permanently_drop_suid(getuid()); 1270 close(from[0]); 1271 if (dup2(from[1], STDOUT_FILENO) < 0) 1272 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1273 close(to[1]); 1274 if (dup2(to[0], STDIN_FILENO) < 0) 1275 fatal("ssh_keysign: dup2: %s", strerror(errno)); 1276 close(from[1]); 1277 close(to[0]); 1278 execl(_PATH_SSH_KEY_SIGN, _PATH_SSH_KEY_SIGN, (char *) 0); 1279 fatal("ssh_keysign: exec(%s): %s", _PATH_SSH_KEY_SIGN, 1280 strerror(errno)); 1281 } 1282 close(from[1]); 1283 close(to[0]); 1284 1285 buffer_init(&b); 1286 buffer_put_int(&b, packet_get_connection_in()); /* send # of socket */ 1287 buffer_put_string(&b, data, datalen); 1288 if (ssh_msg_send(to[1], version, &b) == -1) 1289 fatal("ssh_keysign: couldn't send request"); 1290 1291 if (ssh_msg_recv(from[0], &b) < 0) { 1292 error("ssh_keysign: no reply"); 1293 buffer_free(&b); 1294 return -1; 1295 } 1296 close(from[0]); 1297 close(to[1]); 1298 1299 while (waitpid(pid, &status, 0) < 0) 1300 if (errno != EINTR) 1301 break; 1302 1303 if (buffer_get_char(&b) != version) { 1304 error("ssh_keysign: bad version"); 1305 buffer_free(&b); 1306 return -1; 1307 } 1308 *sigp = buffer_get_string(&b, lenp); 1309 buffer_free(&b); 1310 1311 return 0; 1312 } 1313 1314 int 1315 userauth_hostbased(Authctxt *authctxt) 1316 { 1317 Key *private = NULL; 1318 Sensitive *sensitive = authctxt->sensitive; 1319 Buffer b; 1320 u_char *signature, *blob; 1321 char *chost, *pkalg, *p, myname[NI_MAXHOST]; 1322 const char *service; 1323 u_int blen, slen; 1324 int ok, i, len, found = 0; 1325 1326 /* check for a useful key */ 1327 for (i = 0; i < sensitive->nkeys; i++) { 1328 private = sensitive->keys[i]; 1329 if (private && private->type != KEY_RSA1) { 1330 found = 1; 1331 /* we take and free the key */ 1332 sensitive->keys[i] = NULL; 1333 break; 1334 } 1335 } 1336 if (!found) { 1337 debug("No more client hostkeys for hostbased authentication."); 1338 return 0; 1339 } 1340 if (key_to_blob(private, &blob, &blen) == 0) { 1341 key_free(private); 1342 return 0; 1343 } 1344 /* figure out a name for the client host */ 1345 p = NULL; 1346 if (packet_connection_is_on_socket()) 1347 p = get_local_name(packet_get_connection_in()); 1348 if (p == NULL) { 1349 if (gethostname(myname, sizeof(myname)) == -1) { 1350 verbose("userauth_hostbased: gethostname: %s", 1351 strerror(errno)); 1352 } else 1353 p = xstrdup(myname); 1354 } 1355 if (p == NULL) { 1356 error("userauth_hostbased: cannot get local ipaddr/name"); 1357 key_free(private); 1358 xfree(blob); 1359 return 0; 1360 } 1361 len = strlen(p) + 2; 1362 xasprintf(&chost, "%s.", p); 1363 debug2("userauth_hostbased: chost %s", chost); 1364 xfree(p); 1365 1366 service = datafellows & SSH_BUG_HBSERVICE ? "ssh-userauth" : 1367 authctxt->service; 1368 pkalg = xstrdup(key_ssh_name(private)); 1369 buffer_init(&b); 1370 /* construct data */ 1371 buffer_put_string(&b, session_id2, session_id2_len); 1372 buffer_put_char(&b, SSH2_MSG_USERAUTH_REQUEST); 1373 buffer_put_cstring(&b, authctxt->server_user); 1374 buffer_put_cstring(&b, service); 1375 buffer_put_cstring(&b, authctxt->method->name); 1376 buffer_put_cstring(&b, pkalg); 1377 buffer_put_string(&b, blob, blen); 1378 buffer_put_cstring(&b, chost); 1379 buffer_put_cstring(&b, authctxt->local_user); 1380 #ifdef DEBUG_PK 1381 buffer_dump(&b); 1382 #endif 1383 if (sensitive->external_keysign) 1384 ok = ssh_keysign(private, &signature, &slen, 1385 buffer_ptr(&b), buffer_len(&b)); 1386 else 1387 ok = key_sign(private, &signature, &slen, 1388 buffer_ptr(&b), buffer_len(&b)); 1389 key_free(private); 1390 buffer_free(&b); 1391 if (ok != 0) { 1392 error("key_sign failed"); 1393 xfree(chost); 1394 xfree(pkalg); 1395 xfree(blob); 1396 return 0; 1397 } 1398 packet_start(SSH2_MSG_USERAUTH_REQUEST); 1399 packet_put_cstring(authctxt->server_user); 1400 packet_put_cstring(authctxt->service); 1401 packet_put_cstring(authctxt->method->name); 1402 packet_put_cstring(pkalg); 1403 packet_put_string(blob, blen); 1404 packet_put_cstring(chost); 1405 packet_put_cstring(authctxt->local_user); 1406 packet_put_string(signature, slen); 1407 memset(signature, 's', slen); 1408 xfree(signature); 1409 xfree(chost); 1410 xfree(pkalg); 1411 xfree(blob); 1412 1413 packet_send(); 1414 return 1; 1415 } 1416 1417 /* find auth method */ 1418 1419 /* 1420 * given auth method name, if configurable options permit this method fill 1421 * in auth_ident field and return true, otherwise return false. 1422 */ 1423 static int 1424 authmethod_is_enabled(Authmethod *method) 1425 { 1426 if (method == NULL) 1427 return 0; 1428 /* return false if options indicate this method is disabled */ 1429 if (method->enabled == NULL || *method->enabled == 0) 1430 return 0; 1431 /* return false if batch mode is enabled but method needs interactive mode */ 1432 if (method->batch_flag != NULL && *method->batch_flag != 0) 1433 return 0; 1434 return 1; 1435 } 1436 1437 static Authmethod * 1438 authmethod_lookup(const char *name) 1439 { 1440 Authmethod *method = NULL; 1441 if (name != NULL) 1442 for (method = authmethods; method->name != NULL; method++) 1443 if (strcmp(name, method->name) == 0) 1444 return method; 1445 debug2("Unrecognized authentication method name: %s", name ? name : "NULL"); 1446 return NULL; 1447 } 1448 1449 /* XXX internal state */ 1450 static Authmethod *current = NULL; 1451 static char *supported = NULL; 1452 static char *preferred = NULL; 1453 1454 /* 1455 * Given the authentication method list sent by the server, return the 1456 * next method we should try. If the server initially sends a nil list, 1457 * use a built-in default list. 1458 */ 1459 static Authmethod * 1460 authmethod_get(char *authlist) 1461 { 1462 char *name = NULL; 1463 u_int next; 1464 1465 /* Use a suitable default if we're passed a nil list. */ 1466 if (authlist == NULL || strlen(authlist) == 0) 1467 authlist = options.preferred_authentications; 1468 1469 if (supported == NULL || strcmp(authlist, supported) != 0) { 1470 debug3("start over, passed a different list %s", authlist); 1471 if (supported != NULL) 1472 xfree(supported); 1473 supported = xstrdup(authlist); 1474 preferred = options.preferred_authentications; 1475 debug3("preferred %s", preferred); 1476 current = NULL; 1477 } else if (current != NULL && authmethod_is_enabled(current)) 1478 return current; 1479 1480 for (;;) { 1481 if ((name = match_list(preferred, supported, &next)) == NULL) { 1482 debug("No more authentication methods to try."); 1483 current = NULL; 1484 return NULL; 1485 } 1486 preferred += next; 1487 debug3("authmethod_lookup %s", name); 1488 debug3("remaining preferred: %s", preferred); 1489 if ((current = authmethod_lookup(name)) != NULL && 1490 authmethod_is_enabled(current)) { 1491 debug3("authmethod_is_enabled %s", name); 1492 debug("Next authentication method: %s", name); 1493 return current; 1494 } 1495 } 1496 } 1497 1498 static char * 1499 authmethods_get(void) 1500 { 1501 Authmethod *method = NULL; 1502 Buffer b; 1503 char *list; 1504 1505 buffer_init(&b); 1506 for (method = authmethods; method->name != NULL; method++) { 1507 if (authmethod_is_enabled(method)) { 1508 if (buffer_len(&b) > 0) 1509 buffer_append(&b, ",", 1); 1510 buffer_append(&b, method->name, strlen(method->name)); 1511 } 1512 } 1513 buffer_append(&b, "\0", 1); 1514 list = xstrdup(buffer_ptr(&b)); 1515 buffer_free(&b); 1516 return list; 1517 } 1518